Pump.



G I V 0 MP 0U DP R A APPLICATION FILED NOV. 14, 1902.

N0 MODEL.

W lime/afar gltzlailaadavmzp rzjc ATENT OFFICE.

ANDREAS RADOVANOVIO, OF ZURICH, SWITZERLAND.

PUMP.

ISEECIFIOATION forming part of Letters Patent No. 722,142, dated March 3, 1903.

Application filed November 14, 1902. Serial No. 131,427. (No model.)

To (tZZ 11/72/0722, it may concern:

Beit known thatLANDREAsRADovANovm, a subject of the Emperor of Austria-Hungary, residing at Zurich, in the Republic of Switzerland, have invented certain new and useful Improvements in Pumps, of which the following is a specification.

This invention relates to pumps, and according thereto a pump is provided with apparatus which is adapted before the commencement of the suction-stroke of the pump to generate below the suction-valve a hydraulic pressure that will facilitate the opening of the suction-valve and the flow into the pump-barrel of the liquid to be conveyed, and so prevent the disruption of the column of liquid during the suction-stroke, and before the commencement of the delivery-stroke to generate under the suction-valve a steadilyincreasing hydraulic pressure which just before the change of stroke will become nearly equal to that exerted by the plunger of the pump during its delivery-stroke, so that the slight excess of pressure in the barrel which will thereupon ensue will cause the suctionvalve to be closed Without shock.

In the accompanying drawings, forming a part of this specification, Figure 1 is a sectional View of a pump constructed in accordance with my invention; Fig. 2, adetail sectional view of the piston 1) shown in Fig. 1; Fig. 3, a sectional view illustrating a moditied construction of chamber m and piston c; Fig. 4, another modification wherein two valves are employed in place of the piston c; Fig. 5, a further modification; Fig. 6, a diagrammatic View, the pump being shown in elevation, of a modified construction for operating the piston '22; Fig. 7, another modified arrangement of the invention, and Fig. 8 a detail sectional view of the piston shown in Fig. 7.

Under the suction-valve s, Fig. 1, there is a chamber m, which is separated from the suction air chamber and suction-pipe w by means of a contracted portion 0, in which a piston o is moved by mechanism resembling valve-gear. A suitable clearancep is left between and c. This arrangement operates as follows: When, as shown in Fig. 1, the pump is at the commencement of its suctionstroke and its plunger is at the dead-point,the

eccentric e, which operates the piston v by means of the linkwork c, has already passed beyond its dead-point and tends to move the piston 12 upward, and thereby force liquid from the chamber m into the chamber to through the clearance p. Owing, however,

to the throttling of the liquid, there arises in the chamber m a hydraulic pressure, which on the commencement of the suction-stroke of the pump at once opens the suction-valve and drives the liquid into the pump. When on further movement the piston c has left the contraction c, as shown by dotted lines, the hydraulic pressure in the chamber 112 ceases and the pump then draws its supply directly from the chamber to. In order that the hydraulic pressure produced by the piston 12 may be gradually merged into that produced directly by the suction of the pump, the contraction c is so formed as gradually to augment the clearance between 0 and o. The piston 11, as shown in Fig. 2, is provided with a flap-valve o, opening upward. The liquid passes through this valve from w to on without throttling both during the suctionstroke of the pump and during the downward movement of the piston c. As the plunger toward the end of its suction-stroke approaches its extreme outward position the piston '12 is again moved upward into the contracted portion 0. This may be effected by causing the shaft which actuates the eccentric e to make two revolutions for each revolution of the pump-shaft which operates the plunger, or the mechanism shown in Fig; 6 may be employed, wherein each revolution of the shaft or of the eccentric 6 causes the lever e to make two oscillations. Through the entry of the piston i) into the chamber m there is again generated in this chamber a hydraulic pressure, which as long as the suction-stroke continues is transmitted to the pump-barrel. By adopting suitable proportions for the cross-sections of the piston 'v and the clearance p in relation to the speed of the piston the pressure'generated by the piston v at the dead-point of the pump-plunger can be increased until it is nearly equal to that exerted by the plunger during its delivery-stroke. Now at the instant that the plunger changes its direction of movement and commences its delivery-stroke the hydraulic pressure produced in the chamber m by the piston o simultaneously begins slowly to diminish, as it may be caused to do by giving a suitable form to the contraction c or the piston 11, and the suction-valve will be closed by a very slight excess of pressure on its upper side, and consequently without shock. A special valvegear may, however, in some cases be provided to effect at this instant the closure of the valve. I

Instead of doubling the rate of rotation of the shaft which actuates the piston 11 or of employing the mechanism shown in Fig. 6 the piston 11 may, as shown in Fig. 7, be formed as a hollow double-beat valve, which makes the same number of strokes as the pumpplunger and can be driven directly from the pump-shaft, but which during both its upward and its downward movement generates a hydraulic pressure in the chamber m. The piston 21 when formed as just described is provided with a valve *0, opening upward, analogous to the valve 12 already referred to with reference to and shown in Fig. 2, and a second valve 1 through which the liquid can enter into the chamber m, is located either on the casing, Fig. 7, or on the piston v, Fig. 8. The arrows m and y show the direction of the movement of the piston 12 prior to the commencement of the suction-stroke and the delivery-stroke, respectively. The arrows 00;

and y show the corresponding directions of flow of the liquid. The piston o during its movement in the direction of the arrow 00 operates with the diflerence of cross-section corresponding to the diameters d and d and generates a hydraulic pressure both in the chamber 'm and also in the chamber 'm. During the movement of the piston o in the direction of the arrow y it works with a surface corresponding to d and generates hydraulic pressure only in the chamber m. In other respects the method of operation of this doubleacting piston 'u is just the same as that of the single-action arrangement, which runs at twice the speed.

I Fig. 3 shows an arrangement wherein the piston '11 is adapted to be oscillated and has its valve 0; formed as a flap on its side toward the suction-valve s, as shown by dotted lines. In the example shown in Fig. 4. the valve 11 is arranged separately from the piston 1;.

Fig. 5 shows a modification wherein the piston o is formed as a plunger and the valve '0, which, as in the example shown in Fig. 4, is separate from the piston '2), does not even when in its lowest position entirely close, but leaves a clearance 79, which in this case will be constant and through which the liquid forced by the piston '11 from m to w escapes. After the hydraulic pressure in 111 has ceased, the pump on the acceleration of its plunger draws liquid directly through the valve '0'.

In order to prevent excessive rise of pressure in the chamber m, a suitably-loaded safety-valve 2, opening from the chamber 0% into the chamber w, may be provided both in the arrangement just referred to and in those previously described.

The piston '0 may be operated from the pump-shaft by any convenient mechanical or hydraulic means, and the position and the direction of movement of the piston o in relation to the axis of the suction-valve s can be arranged as desired.

The piston '12 and the aperture corresponding thereto in the contracted portion 0 may be of any desired form. For an oscillating piston, for instance, the rectangular form will be the most suitable.

The improvements herein described are applicable to pumps and pump-valves of all kinds.

1. In a pump, a pump-cylinder, a pumppiston in said cylinder, means for operating said piston, a valve opening into said cylinder, a chamber adjacent to said valve, a compression-valve in said chamber, and means for operating said compression-valve immediately before the beginning and the end of the stroke of said pump-piston.

2. In a pump, a pump-cylinder, a pumppiston in said cylinder, a valve opening into said cylinder, a chamber adjacent to said valve, a compression-valve in said chamber, an eccentric for operating said pump-piston, and an eccentric for operating said compression-valve immediately before the beginning and the end of the stroke of said pump-pisten.

3. In a pump, a pump-cylinder, a pumppiston in said cylinder, means for operating said piston, a valve opening into said cylinder, a chamber adjacent to said valve, and means for creating hydrostatic pressure in said chamber immediately before the beginning and the end of the stroke of said pumppiston.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

. ANDREAS RADOVANOVIO. Witnesses:

A. LIEBERKNEOHT, ARNOLD Gaosz. 

